Re: RAID question-ATA133 hard disc and hard discs connection
Hi Ed Baily, Thanks for your advice. At 03:58 PM 12/25/2001 -0500, you wrote: >Stephen> I have some further RAID questions to ask : > >I suggest doing a google search on "RAID", and doing some reading to learn >more about RAID... Yes, you are correct. I already made intensive browsing on Internet in the past including using google.com. I have a huge bundles of RAID documents as well as advice from those guys on this list and other lists as well. I am very appreciated for their effort in assisting me. However the more I go through the technical document more confusion I have. I think that I have to gain some practical experience rather than merely going through papers. Prior to start I have to select a right direction rather than picking up a wrong controller card. For such a reason I start sending postings to this list with a hope to have a collective advice from other guys. For example : RAID 3 I have been trying to find its IDE-controller card both from Internet and shopping around computer firms as well but I could not get its information. Some shop told me that it is only available on SCSI. Thanks and Merry X'Mas B.R. Stephen ___ Redhat-list mailing list [EMAIL PROTECTED] https://listman.redhat.com/mailman/listinfo/redhat-list
Re: RAID question-ATA133 hard disc and hard discs connection
> "Stephen" == Stephen Liu <[EMAIL PROTECTED]> writes: Stephen> I have some further RAID questions to ask : I suggest doing a google search on "RAID", and doing some reading to learn more about RAID... Ed -- Ed BaileyRed Hat, Inc. http://www.redhat.com/ ___ Redhat-list mailing list [EMAIL PROTECTED] https://listman.redhat.com/mailman/listinfo/redhat-list
Re: RAID Question !
> "christoph" == christoph pirchl <[EMAIL PROTECTED]> writes: ... christoph> You forgot RAID 4 it is stripping with parity on one Disc ! It s christoph> normally not used any longer as i know ! Actually, a few years back I sat in on a presentation put on by Network Appliance. It seems that they (at least at that time) used RAID 4. The downside to RAID 4 is that the parity drive is normally the bottleneck (since the parity must be written to with every write I/O -- no matter which of the other drives are written to, the parity drive gets hit as well) It seems that Network Appliance's log-structured filesystem got around the problem by somehow reducing the parity drive's I/O load. Then, because the rest of the drives in a RAID 4 array follow a set pattern of sector interleaving, it was possible to allow additional drives to be added into the array dynamically -- it was a pretty cool solution to a tough problem... Ed -- Ed BaileyRed Hat, Inc. http://www.redhat.com/ ___ Redhat-list mailing list [EMAIL PROTECTED] https://listman.redhat.com/mailman/listinfo/redhat-list
Re: RAID Question !
On Tue, 2001-12-18 at 07:50, [EMAIL PROTECTED] wrote: > Sorry do correct you Ed, but > > RAID 5 is not striping + mirroring, it is stripping with distributed > parity, If I said RAID 5 is striping + mirroring, then you're right - I was wrong. > It is the best compromise when you need fault tolerance, it`s cheaper > then > RAID 1 (mirroring) and the fault tolerance is also ok ! I have a lot of RAID 5 storage at work. In fact, I use controller-based RAID 5 (on redundant controllers) and then use hosts in separate data centers to mirror the storage. This gives me fault tolerance as well as disaster tolerance. > You forgot RAID 4 it is stripping with parity on one Disc ! It s > normally not used any longer as i know ! Ditto for RAID 3. There are bunch of other obscure RAID implementations, although most are not officially recognized by the RAB (Raid Advisory Board) but made up in vendors' mind and sold like a standard. RAID 7 and RAID S are among these. Cheers, .../Ed -- Ed Wilts, Mounds View, MN, USA mailto:[EMAIL PROTECTED] ___ Redhat-list mailing list [EMAIL PROTECTED] https://listman.redhat.com/mailman/listinfo/redhat-list
Re: RAID Question !
Sorry do correct you Ed, but RAID 5 is not striping + mirroring, it is stripping with distributed parity, It is the best compromise when you need fault tolerance, it`s cheaper then RAID 1 (mirroring) and the fault tolerance is also ok ! You forgot RAID 4 it is stripping with parity on one Disc ! It s normally not used any longer as i know ! best wishes Chris ___ Redhat-list mailing list [EMAIL PROTECTED] https://listman.redhat.com/mailman/listinfo/redhat-list
Re: RAID question
Thank Ed B.R. Stephen At 11:06 AM 12/19/2001 -0600, you wrote: >On Thu, Dec 20, 2001 at 12:30:10AM +0800, Stephen Liu wrote: > > > > Whether a special controller with 3 channels for connecting 3 hard > > > discs is > > > > needed ? > >You'll typically see 3-channel RAID controllers provide for 3 SCSI buses, not >3 ATA buses. Multiple drives on a SCSI bus can have I/O pending at the same >time - this is not true on ATA drives. > > > 1) Is RAID 5 controller differs from other controller in design ? > >Typically a RAID 5 controller has write-back cache to help you with the >performance hit you take when writing to RAID-5 sets. > > > 2) How many channels it has ? > >That's up to the vendor. It varies from 1 to a number well outside your >budget... > > > 3) If it has 3 channels only, how can I connect 5 hard discs to > > it? Therefore I have to connect 2 hard discs as slave. > >As I said, 3-channel RAID controllers are typically SCSI, and there is no >master/slave concept. > >-- >Ed Wilts, Mounds View, MN, USA >mailto:[EMAIL PROTECTED] ___ Redhat-list mailing list [EMAIL PROTECTED] https://listman.redhat.com/mailman/listinfo/redhat-list
Re: RAID question
Hi Leonard, Thanks. I got it. B.R. Stephen At 03:10 PM 12/19/2001 +0100, you wrote: > Hi Stephen, > > > Is RAID 0+1 similar to RAID 5 in function/performance ? > > I think I answered this question in my last post in this thread. > > Bye, > > Leonard. ___ Redhat-list mailing list [EMAIL PROTECTED] https://listman.redhat.com/mailman/listinfo/redhat-list
Re: RAID question
On Thu, Dec 20, 2001 at 12:30:10AM +0800, Stephen Liu wrote: > > > Whether a special controller with 3 channels for connecting 3 hard > > discs is > > > needed ? You'll typically see 3-channel RAID controllers provide for 3 SCSI buses, not 3 ATA buses. Multiple drives on a SCSI bus can have I/O pending at the same time - this is not true on ATA drives. > 1) Is RAID 5 controller differs from other controller in design ? Typically a RAID 5 controller has write-back cache to help you with the performance hit you take when writing to RAID-5 sets. > 2) How many channels it has ? That's up to the vendor. It varies from 1 to a number well outside your budget... > 3) If it has 3 channels only, how can I connect 5 hard discs to > it? Therefore I have to connect 2 hard discs as slave. As I said, 3-channel RAID controllers are typically SCSI, and there is no master/slave concept. -- Ed Wilts, Mounds View, MN, USA mailto:[EMAIL PROTECTED] ___ Redhat-list mailing list [EMAIL PROTECTED] https://listman.redhat.com/mailman/listinfo/redhat-list
Re: RAID question
Hi Ed, Thanks for your detail answer to my questions and time spent. At 06:41 AM 12/19/2001 -0600, you wrote: >On Tue, 2001-12-18 at 23:04, Stephen Liu wrote: > > > At 06:40 AM 12/18/2001 -0600, you wrote: > > >RAID 5 is striping + mirroring. I recommend that this not be done on > > >IDE drives unless you've invested in extra controllers. You need at > > >least 3 drives to make a RAID 5 set. > > > > Whether a special controller with 3 channels for connecting 3 hard > discs is > > needed ? > > Or you need 3/5 controllers for 3/5 hard discs ? > > What kind of controller it is ? > >You can do this in hardware or software. Ideally, you always want each >member of a RAIDset on a separate channel, especially with IDE drives >that don't support transfers to multiple devices on the same channel at >the same time. Sorry, I still has not got your answer to this point. 1) Is RAID 5 controller differs from other controller in design ? 2) How many channels it has ? 3) If it has 3 channels only, how can I connect 5 hard discs to it? Therefore I have to connect 2 hard discs as slave. I just found following document from Internet : http://www.linuxgazette.com/issue45/nielsen.html#5 http://linuxdoc.org/HOWTO/Software-RAID-HOWTO-4.html#ss4.6 talking about RAID 5 in brief Thanks B.R. Stephen ___ Redhat-list mailing list [EMAIL PROTECTED] https://listman.redhat.com/mailman/listinfo/redhat-list
Re: RAID question
Hi Stephen, > Is RAID 0+1 similar to RAID 5 in function/performance ? I think I answered this question in my last post in this thread. Bye, Leonard. ___ Redhat-list mailing list [EMAIL PROTECTED] https://listman.redhat.com/mailman/listinfo/redhat-list
Re: RAID question
On Tue, 2001-12-18 at 23:04, Stephen Liu wrote: > At 06:40 AM 12/18/2001 -0600, you wrote: > >RAID 5 is striping + mirroring. I recommend that this not be done on > >IDE drives unless you've invested in extra controllers. You need at > >least 3 drives to make a RAID 5 set. > > Whether a special controller with 3 channels for connecting 3 hard discs is > needed ? > Or you need 3/5 controllers for 3/5 hard discs ? > What kind of controller it is ? You can do this in hardware or software. Ideally, you always want each member of a RAIDset on a separate channel, especially with IDE drives that don't support transfers to multiple devices on the same channel at the same time. > >RAID 0+1 will give you the highest performance at the expense of the > >most drives. > > Is RAID 0+1 similar to RAID 5 in function/performance ? RAID 0+1 is faster for all writes, and a bit slower for reads. > Whether its controller has 4 channels for connnecting 4 hard discs > Can I use only 2 hard discs with partitions for RAID 0+1 instead of 4 hard > discs ? It wouldn't make sense to do RAID 0+1 on only 2 drives. If you stripe (RAID 0) across 2 partitions on the same drive, you'll thrash yourself doing reads. If you mirror across 2 partitions on the same drive, you won't protect yourself against a head crash. > >For a home system, RAID 1 is no longer out of the reach of the average > >PC purchaser. I added 2 40GB ATA100 drives on the Promise TX2 > >controller for about $240. I mirror the first 10GB of data so that > >leaves me 70GB of usuable space. > > To my understanding you use the second hard disc for mirroring. What are > you going to do with 30G partition on the first hard disc ? The un-mirrored 30GB on each drive is for data that doesn't need protection - my backups from other systems, ISO images, etc. > Are you using the primary/secondary channel of your motherboard to connect > a hard disc for backup ? I use the motherboard IDE channels for my CDROM and CD-RW drives. I use the Promise TX2 controller for my ATA100 drives. .../Ed -- Ed Wilts, Mounds View, MN, USA mailto:[EMAIL PROTECTED] ___ Redhat-list mailing list [EMAIL PROTECTED] https://listman.redhat.com/mailman/listinfo/redhat-list
Re: RAID question
Hi James, Thanks for your information. Where can I have that chapter downloaded ? Is its ebook available ? B.R. Stephen At 03:33 AM 12/19/2001 -0700, you wrote: >Hi, the Berkley Raid definitions define RAID 5 as striping with interleved >parity. because of the number of increased writes and read to commit an >actual write to disk, this method is normally used with caching in RAM >using fast writes as a method to improve performance. Striping + >Mirroring is RAID 0+1, and Mirroring + Striping is RAID 1+0. If you have >a choice use RAID 1+0 even though it requires twice the number of disks >and or controllers. The reference for all of this stuff >is "Configuration and Capacity Planning for Solaris Servers" Chapter >7.It is required reading even if you are on another hardware platform, >because the generic information is invaluable. > >James Hartley > > > >Ed Wilts wrote: >> >>On Mon, 2001-12-17 at 23:27, Stephen Liu wrote: >> >>> >>>One additional question I expect to ask, in my case, whether it is >>>advisable to apply RAID to build the Web Server simultaneously because the >>>configuration of Apache, PHP, MySQL will keep me quite busy (I did it once >>>in 2 years ago). Is RAID difficult to set up ? Which RAID, RAID 0+1, >>>RAID 5, etc. shall be more applicable to my case ? >> >> >>RAID 0 is striping and is used *only* for performance reasons. If you >>don't think you'll need the additional performance, don't use it. You >>will lose redundancy in favor of the performance. If either drive >>fails, you lose your data. >> >>RAID 1 is mirroring. When you do your initial Red Hat Linux 7.2 >>install, you can configure this, and it's easy - it's well documented in >>the Installation Guide and takes an extra 5 or 10 minutes to set up, and >>then it just runs without you having to do anything else. It's what I >>run at home. >> >>RAID 5 is striping + mirroring. I recommend that this not be done on >>IDE drives unless you've invested in extra controllers. You need at >>least 3 drives to make a RAID 5 set. >> >>RAID 0+1 will give you the highest performance at the expense of the >>most drives. >> >>For a home system, RAID 1 is no longer out of the reach of the average >>PC purchaser. I added 2 40GB ATA100 dri >>ves on the Promise TX2 >>controller for about $240. I mirror the first 10GB of data so that >>leaves me 70GB of usuable space. That's a lot of disk space for not a >>lot of money. A few years ago, this would have been prohibitively >>expensive. Naturally, I still do backups of my data (to hard drives, >>not tape). >> ___ Redhat-list mailing list [EMAIL PROTECTED] https://listman.redhat.com/mailman/listinfo/redhat-list
Re: RAID question
Hi, the Berkley Raid definitions define RAID 5 as striping with interleved parity. because of the number of increased writes and read to commit an actual write to disk, this method is normally used with caching in RAM using fast writes as a method to improve performance. Striping + Mirroring is RAID 0+1, and Mirroring + Striping is RAID 1+0. If you have a choice use RAID 1+0 even though it requires twice the number of disks and or controllers. The reference for all of this stuff is "Configuration and Capacity Planning for Solaris Servers" Chapter 7. It is required reading even if you are on another hardware platform, because the generic information is invaluable. James Hartley Ed Wilts wrote: [EMAIL PROTECTED]"> On Mon, 2001-12-17 at 23:27, Stephen Liu wrote: One additional question I expect to ask, in my case, whether it is advisable to apply RAID to build the Web Server simultaneously because the configuration of Apache, PHP, MySQL will keep me quite busy (I did it once in 2 years ago). Is RAID difficult to set up ? Which RAID, RAID 0+1, RAID 5, etc. shall be more applicable to my case ? RAID 0 is striping and is used *only* for performance reasons. If youdon't think you'll need the additional performance, don't use it. Youwill lose redundancy in favor of the performance. If either drivefails, you lose your data. RAID 1 is mirroring. When you do your initial Red Hat Linux 7.2install, you can configure this, and it's easy - it's well documented inthe Installation Guide and takes an extra 5 or 10 minutes to set up, andthen it just runs without you having to do anything else. It's what Irun at home.RAID 5 is striping + mirroring. I recommend that this not be done onIDE drives unless you've invested in extra controllers. You need atleast 3 drives to make a RAID 5 set.RAID 0+1 will give you the highest performance at the expense of themost drives.For a home system, RAID 1 is no longer out of the reach of the averagePC purchaser. I added 2 40GB ATA100 dri ves on the Promise TX2controller for about $240. I mirror the first 10GB of data so thatleaves me 70GB of usuable space. That's a lot of disk space for not alot of money. A few years ago, this would have been prohibitivelyexpensive. Naturally, I still do backups of my data (to hard drives,not tape).
Re: RAID question
Hi, Thanks for your detail information. At 06:40 AM 12/18/2001 -0600, you wrote: >RAID 5 is striping + mirroring. I recommend that this not be done on >IDE drives unless you've invested in extra controllers. You need at >least 3 drives to make a RAID 5 set. Whether a special controller with 3 channels for connecting 3 hard discs is needed ? Or you need 3/5 controllers for 3/5 hard discs ? What kind of controller it is ? >RAID 0+1 will give you the highest performance at the expense of the >most drives. Is RAID 0+1 similar to RAID 5 in function/performance ? Whether its controller has 4 channels for connnecting 4 hard discs Can I use only 2 hard discs with partitions for RAID 0+1 instead of 4 hard discs ? >For a home system, RAID 1 is no longer out of the reach of the average >PC purchaser. I added 2 40GB ATA100 drives on the Promise TX2 >controller for about $240. I mirror the first 10GB of data so that >leaves me 70GB of usuable space. To my understanding you use the second hard disc for mirroring. What are you going to do with 30G partition on the first hard disc ? Are you using the primary/secondary channel of your motherboard to connect a hard disc for backup ? Thanks B.R. Stephen ___ Redhat-list mailing list [EMAIL PROTECTED] https://listman.redhat.com/mailman/listinfo/redhat-list
Re: RAID question hpt370
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Generic Account 0568 wrote: >is there a way to get the module to load up on kernel other then 2.4.2-2 >right now the the only way i can get it working is using the kernel that >comes withe the driver every time i try antoher i get unresolved symbles >errors on the scsi The HighPoint 370 is an IDE chip. The SCSI errors are unrelated, and suggest that maybe you're missing some other module, or something else is out of whack in your kernel setup. That chip is fine with all stock Red Hat kernels from 7.1 on forward ... try updating? - -d - -- David Talkington PGP key: http://www.prairienet.org/~dtalk/0xCA4C11AD.pgp -BEGIN PGP SIGNATURE- Version: PGP 6.5.8 Comment: Made with pgp4pine 1.75-6 iQA/AwUBPB/9U79BpdPKTBGtEQKUCACg8AXy2uwwq17iDbMZ1uJZmGGFok8AoPGV tysW2LqRaEzfmNh7abbT3ElV =AGC1 -END PGP SIGNATURE- ___ Redhat-list mailing list [EMAIL PROTECTED] https://listman.redhat.com/mailman/listinfo/redhat-list
Re: RAID question
On Mon, 2001-12-17 at 23:27, Stephen Liu wrote: > One additional question I expect to ask, in my case, whether it is > advisable to apply RAID to build the Web Server simultaneously because the > configuration of Apache, PHP, MySQL will keep me quite busy (I did it once > in 2 years ago). Is RAID difficult to set up ? Which RAID, RAID 0+1, > RAID 5, etc. shall be more applicable to my case ? RAID 0 is striping and is used *only* for performance reasons. If you don't think you'll need the additional performance, don't use it. You will lose redundancy in favor of the performance. If either drive fails, you lose your data. RAID 1 is mirroring. When you do your initial Red Hat Linux 7.2 install, you can configure this, and it's easy - it's well documented in the Installation Guide and takes an extra 5 or 10 minutes to set up, and then it just runs without you having to do anything else. It's what I run at home. RAID 5 is striping + mirroring. I recommend that this not be done on IDE drives unless you've invested in extra controllers. You need at least 3 drives to make a RAID 5 set. RAID 0+1 will give you the highest performance at the expense of the most drives. For a home system, RAID 1 is no longer out of the reach of the average PC purchaser. I added 2 40GB ATA100 drives on the Promise TX2 controller for about $240. I mirror the first 10GB of data so that leaves me 70GB of usuable space. That's a lot of disk space for not a lot of money. A few years ago, this would have been prohibitively expensive. Naturally, I still do backups of my data (to hard drives, not tape). -- Ed Wilts, Mounds View, MN, USA mailto:[EMAIL PROTECTED] ___ Redhat-list mailing list [EMAIL PROTECTED] https://listman.redhat.com/mailman/listinfo/redhat-list
Re: RAID question
Hi Leonard, Lot of thanks for your detail information and time I shall digest those documentation first before finalizing my way to go.RAID 0, RAID 1, or RAID 5 , etc.? My plan is to build a Web Server using Apache, PHP, MySQL, etc. to experience its function. I hesitate whether I should use RAID simultaneously at start. Because I have been away from Linux for sometime, almost 2 years and coming back recently. Therefore I have to refresh my technical memory on all commands, some of them having be changed or replaced which keeps me quite busy. Hardware is not a problem to me. I am in electronic industry manufacturing PSTN phones, having certain knowledge on uC (micro-controller). One additional question I expect to ask, in my case, whether it is advisable to apply RAID to build the Web Server simultaneously because the configuration of Apache, PHP, MySQL will keep me quite busy (I did it once in 2 years ago). Is RAID difficult to set up ? Which RAID, RAID 0+1, RAID 5, etc. shall be more applicable to my case ? Thanks in advance. B.R. Stephen At 11:01 PM 12/17/2001 +0100, you wrote: > Hi Stephen, > > > I am using 2th Max 8KHA motherboard. Unfortunately it has only one FDD1 > > channel for ATA100 hard disc. Additionally it has 2 ATA33 IDE channels > > (altogether 3 channels). If I add an ATA100 controller then I shall have 3 > > ATA100 channels, having a waste (5 channels). > > The ATA33 channels will probably not slow your array down too much, as long >as you put each disk on a separate controller. Most disks will not saturate >the bus, although some modern 7200 rpm drives will. You will probably still >have quite a speed increment anyway. But of course, if you need the speed and >you have brand new 7200 rpm drives get yourself an extra ATA100 controller. > > > Could I use 2 hard discs having different specification and capacity ? > > Yes, but if you don't want to waste any space you will create partitions > that >are of equal size to construct the RAID array, ie, if hda1 and hdc1 are in >one >array you will want to make them similarly sized. > > > Could you please explain a little bid in detail, to mirror first few > > partitions on each hard disc ? How many hard disc you install ? 4 > hard discs > > to achieve RAID 0 + 1 ? > > Yes. (At least) four disks for RAID10. You could stripe more than two disks >as well. RAID10 is probably the best if you want both redundancy and (write) >speed, but you "waste" half of the disks. RAID5 is probably a better idea, >because you use n + 1 disks instead of 2n. As said in my previous post read >speed is great with RAID5, but don't expect any improvements in write speed. >The array I constructed writes as fast as a single disk on the Promise >controller. Writing to the onboard controller is a little slower, so you >could >argue write speed increases for the array a little as well. > It is definitely important you tweak the block sizes and parity algorithm >(the installer (for 7.1) doesn't allow the choice of the parity algorithm, so >you should create the RAID devices before or after you install). Recreate the >array with different block sizes (8k was best in my case) and time a dd of a >few hundred megs to see the difference. Wait with the timing until the device >is fully recreated (run top to see if the raid module is using up a lot of >CPU >time). If you are using RAID10 you will have to try quite some >permutations of >blocksizes for the stripes as well as the mirror. > Don't forget to check out the Software-RAID-HOWTO, which you can find under >/usr/share/doc/HOWTO if you installed the howto rpm. > > Bye, > > Leonard. ___ Redhat-list mailing list [EMAIL PROTECTED] https://listman.redhat.com/mailman/listinfo/redhat-list
Re: RAID question
Hi, Ed Wilts, Lot of thanks for your information. I shall sum up all advices sent to me from those guys on the list first in parallel penetrating relevant documentation before finalizing my way to go.RAID 0, RAID 1, or RAID 5 , etc.? My plan is to build a Web Server using Apache, PHP, MySQL, etc. to experience its function. I hesitate whether I should use RAID simultaneously at start. Because I have been away from Linux for sometime, almost 2 years and coming back recently. Therefore I have to refresh my technical memory on all commands, some of them having be changed or replaced which keeps me quite busy. Hardware is not a problem to me. I am in electronic industry manufacturing PSTN phones, having certain knowledge on uC (micro-controller). One additional question I expect to ask, in my case, whether it is advisable to apply RAID to build the Web Server simultaneously because the configuration of Apache, PHP, MySQL will keep me quite busy (I did it once in 2 years ago). Is RAID difficult to set up ? Which RAID, RAID 0+1, RAID 5, etc. shall be more applicable to my case ? Thanks in advance. B.R. Stephen At 12:04 PM 12/17/2001 -0600, you wrote: >On Tue, Dec 18, 2001 at 01:32:20AM +0800, Stephen Liu wrote: > > > > I am using 2th Max 8KHA motherboard. Unfortunately it has only one FDD1 > > channel for ATA100 hard disc. Additionally it has 2 ATA33 IDE channels > > (altogether 3 channels). If I add an ATA100 controller then I shall > have 3 > > ATA100 channels, having a waste (5 channels). Can TX2 ATA100 matches > FDD1 > > in speed ? > >I have no idea how your existing ATA100 controller compares to the TX2. You >could check the specs at Promise's web site or send them e-mail if you really >want to know. > > > Could I use 2 hard discs having different specification and capacity ? > >Probably. I haven't checked Linux's RAID implementation in detail, so I >can't >confirm what happens if you mix and fast and slow drive. You may limit your- >self to the slowest drive speed. As for capacity, the software implemenation >is by partition so you have to make sure that the 2 partitions you're >mirroring are the same size. > > > Could you please explain a little bid in detail, to mirror first few > > partitions on each hard disc ? How many hard disc you install ? 4 hard > > discs to achieve RAID 0 + 1 ? > >I installed 2 hard disks, partitioned each and used RAID-1 for /, /boot, /usr, >/home, and /var. I added swap partitions that aren't mirrored, and then >had 2 spare 10GB partitions on each drive. I don't use RAID-0 - in most >cases, >you don't need (nor want) this. > > >-- >Ed Wilts, Mounds View, MN, USA >mailto:[EMAIL PROTECTED] ___ Redhat-list mailing list [EMAIL PROTECTED] https://listman.redhat.com/mailman/listinfo/redhat-list
Re: RAID question
Hi Stephen, Ed, > Ideally, you'd connect each drive to a separate IDE channel. It doesn't matter > if one is the master on its bus and the other is slave, as long as both drives > are on separate channels. I would suggest you only use the devices as master, or it might be your RAID device is waiting for the master device. The best (fastest) thing to do is to not use any slave devices, or maybe only a cdrom you seldomly use. > I picked up a Promise TX2 ATA/100 controller from http://www.mwave.com for less > than $30 and added 2 new ATA100 40GB drives to it. This makes I/O *very* fast. I made a RAID 5 device with 3 disks using the same controller. Indeed, very fast. Read speeds of twice the speed of a single channel (up to 70 MB/s hdparm -tT values). Write speed about equal to a single disk, but since this is a web server that'll do. CU, Leonard. ___ Redhat-list mailing list [EMAIL PROTECTED] https://listman.redhat.com/mailman/listinfo/redhat-list
Re: RAID question
Hi Stephen, > I am using 2th Max 8KHA motherboard. Unfortunately it has only one FDD1 > channel for ATA100 hard disc. Additionally it has 2 ATA33 IDE channels > (altogether 3 channels). If I add an ATA100 controller then I shall have 3 > ATA100 channels, having a waste (5 channels). The ATA33 channels will probably not slow your array down too much, as long as you put each disk on a separate controller. Most disks will not saturate the bus, although some modern 7200 rpm drives will. You will probably still have quite a speed increment anyway. But of course, if you need the speed and you have brand new 7200 rpm drives get yourself an extra ATA100 controller. > Could I use 2 hard discs having different specification and capacity ? Yes, but if you don't want to waste any space you will create partitions that are of equal size to construct the RAID array, ie, if hda1 and hdc1 are in one array you will want to make them similarly sized. > Could you please explain a little bid in detail, to mirror first few > partitions on each hard disc ? How many hard disc you install ? 4 hard discs > to achieve RAID 0 + 1 ? Yes. (At least) four disks for RAID10. You could stripe more than two disks as well. RAID10 is probably the best if you want both redundancy and (write) speed, but you "waste" half of the disks. RAID5 is probably a better idea, because you use n + 1 disks instead of 2n. As said in my previous post read speed is great with RAID5, but don't expect any improvements in write speed. The array I constructed writes as fast as a single disk on the Promise controller. Writing to the onboard controller is a little slower, so you could argue write speed increases for the array a little as well. It is definitely important you tweak the block sizes and parity algorithm (the installer (for 7.1) doesn't allow the choice of the parity algorithm, so you should create the RAID devices before or after you install). Recreate the array with different block sizes (8k was best in my case) and time a dd of a few hundred megs to see the difference. Wait with the timing until the device is fully recreated (run top to see if the raid module is using up a lot of CPU time). If you are using RAID10 you will have to try quite some permutations of blocksizes for the stripes as well as the mirror. Don't forget to check out the Software-RAID-HOWTO, which you can find under /usr/share/doc/HOWTO if you installed the howto rpm. Bye, Leonard. ___ Redhat-list mailing list [EMAIL PROTECTED] https://listman.redhat.com/mailman/listinfo/redhat-list
Re: RAID question
On Tue, Dec 18, 2001 at 01:32:20AM +0800, Stephen Liu wrote: > > I am using 2th Max 8KHA motherboard. Unfortunately it has only one FDD1 > channel for ATA100 hard disc. Additionally it has 2 ATA33 IDE channels > (altogether 3 channels). If I add an ATA100 controller then I shall have 3 > ATA100 channels, having a waste (5 channels). Can TX2 ATA100 matches FDD1 > in speed ? I have no idea how your existing ATA100 controller compares to the TX2. You could check the specs at Promise's web site or send them e-mail if you really want to know. > Could I use 2 hard discs having different specification and capacity ? Probably. I haven't checked Linux's RAID implementation in detail, so I can't confirm what happens if you mix and fast and slow drive. You may limit your- self to the slowest drive speed. As for capacity, the software implemenation is by partition so you have to make sure that the 2 partitions you're mirroring are the same size. > Could you please explain a little bid in detail, to mirror first few > partitions on each hard disc ? How many hard disc you install ? 4 hard > discs to achieve RAID 0 + 1 ? I installed 2 hard disks, partitioned each and used RAID-1 for /, /boot, /usr, /home, and /var. I added swap partitions that aren't mirrored, and then had 2 spare 10GB partitions on each drive. I don't use RAID-0 - in most cases, you don't need (nor want) this. -- Ed Wilts, Mounds View, MN, USA mailto:[EMAIL PROTECTED] ___ Redhat-list mailing list [EMAIL PROTECTED] https://listman.redhat.com/mailman/listinfo/redhat-list
Re: RAID question
Hi, At 11:06 AM 12/17/2001 -0600, you wrote: >I picked up a Promise TX2 ATA/100 controller from http://www.mwave.com for >less >than $30 and added 2 new ATA100 40GB drives to it. I am using 2th Max 8KHA motherboard. Unfortunately it has only one FDD1 channel for ATA100 hard disc. Additionally it has 2 ATA33 IDE channels (altogether 3 channels). If I add an ATA100 controller then I shall have 3 ATA100 channels, having a waste (5 channels). Can TX2 ATA100 matches FDD1 in speed ? Could I use 2 hard discs having different specification and capacity ? >This makes I/O *very* >fast. I used Linux software-based RAID 1 to mirror my first few partitions >and left 2 un-mirrored partitions to hold data backups. Could you please explain a little bid in detail, to mirror first few partitions on each hard disc ? How many hard disc you install ? 4 hard discs to achieve RAID 0 + 1 ? B.R. Stephen ___ Redhat-list mailing list [EMAIL PROTECTED] https://listman.redhat.com/mailman/listinfo/redhat-list
Re: RAID question
On Tue, Dec 18, 2001 at 12:05:27AM +0800, Stephen Liu wrote: > I am aware of hardware RAID on M$Win OS using a controller connecting to 2 > hard discs. But I am interested to learn whether Linux offers software > controller to connect 2 hard discs. If "Yes" then how to make connection > to 2 discs ? One to Primary IDE another to Secondary IDE, both as master > ? Or to the same IDE, one as master another as slave ? Ideally, you'd connect each drive to a separate IDE channel. It doesn't matter if one is the master on its bus and the other is slave, as long as both drives are on separate channels. The reason for this is that IDE does not allow for simultaneous access to two drives on the same channel. I picked up a Promise TX2 ATA/100 controller from http://www.mwave.com for less than $30 and added 2 new ATA100 40GB drives to it. This makes I/O *very* fast. I used Linux software-based RAID 1 to mirror my first few partitions and left 2 un-mirrored partitions to hold data backups. .../Ed -- Ed Wilts, Mounds View, MN, USA mailto:[EMAIL PROTECTED] ___ Redhat-list mailing list [EMAIL PROTECTED] https://listman.redhat.com/mailman/listinfo/redhat-list
Re: RAID question
Hi Leonard, Thanks for your response and advice. At 03:25 PM 12/17/2001 +0100, you wrote: > The use of RAID 0 with stripes on a single disk is pointless. You want to >stripe to gain performance. But if you use stripes on a single disk you will >probably even loose some performance due to the overhead. Even the use of >separate disks on the same controller is discouraged for IDE. You should use >two disks on separate controllers. I am aware of hardware RAID on M$Win OS using a controller connecting to 2 hard discs. But I am interested to learn whether Linux offers software controller to connect 2 hard discs. If "Yes" then how to make connection to 2 discs ? One to Primary IDE another to Secondary IDE, both as master ? Or to the same IDE, one as master another as slave ? Could you shed me some light ? Thanks in advance. B.R. Stephen > RAID 1 is used where redundancy is needed. Even if you use two disks on >separate controllers the RAID 1 array will probably be somewhat slower than a >single disk for writing. Read speed might be somewhat increased if you choose >the right stripe size. When using two partitions on one disk you can expect >the write speed to drop to half that of a single partition, because >everything >has to be written to two partitions. And if you are lucky read speed does not >drop far below that of a single partition. You will have some redundancy this >way, but it is useless if the disk fails. > Really, if you want to build a RAID system you should go with two disks on >separate controllers at least. > > Bye, > > Leonard. ___ Redhat-list mailing list [EMAIL PROTECTED] https://listman.redhat.com/mailman/listinfo/redhat-list
Re: RAID question
Hi Stephen, Ed, > Yes. Red Hat Linux has offered software RAID for a few years. I do miss a choice of the parity algorithm for RAID 5 in the installer though. Not sure if that was added in 7.2. > > Can I make 4 (four) partitions in the same hard disc and intall RAID 0 and > > RAID 1 to it. Where can I find relevant documentation ? > > RAID 0 on the same disk is not recommended since you'll just be causing > a lot of extra head movement for negative gain. Ditto with RAID 1 - > although you might be able to recover your data if you have a bad spot > on the media, if the head crashes, you're still out of luck. The use of RAID 0 with stripes on a single disk is pointless. You want to stripe to gain performance. But if you use stripes on a single disk you will probably even loose some performance due to the overhead. Even the use of separate disks on the same controller is discouraged for IDE. You should use two disks on separate controllers. RAID 1 is used where redundancy is needed. Even if you use two disks on separate controllers the RAID 1 array will probably be somewhat slower than a single disk for writing. Read speed might be somewhat increased if you choose the right stripe size. When using two partitions on one disk you can expect the write speed to drop to half that of a single partition, because everything has to be written to two partitions. And if you are lucky read speed does not drop far below that of a single partition. You will have some redundancy this way, but it is useless if the disk fails. Really, if you want to build a RAID system you should go with two disks on separate controllers at least. Bye, Leonard. ___ Redhat-list mailing list [EMAIL PROTECTED] https://listman.redhat.com/mailman/listinfo/redhat-list
Re: RAID question
On Mon, 2001-12-17 at 04:24, Stephen Liu wrote: > Is RH7.2 coming with software RAID Yes. Red Hat Linux has offered software RAID for a few years. > Can I make 4 (four) partitions in the same hard disc and intall RAID 0 and > RAID 1 to it. Where can I find relevant documentation ? RAID 0 on the same disk is not recommended since you'll just be causing a lot of extra head movement for negative gain. Ditto with RAID 1 - although you might be able to recover your data if you have a bad spot on the media, if the head crashes, you're still out of luck. Since all writes are now going to have to be doubled, you'll take a massive performance hit. If you were to use 2 drives, you'd be able to parallelize the writes. The Red Hat Linux 7.2 Installation Guide tells you how to set it up at install time. Worked fine for me right out of the box. -- Ed Wilts, Mounds View, MN, USA mailto:[EMAIL PROTECTED] ___ Redhat-list mailing list [EMAIL PROTECTED] https://listman.redhat.com/mailman/listinfo/redhat-list
Re: RAID Question
MPS WebCrew <[EMAIL PROTECTED]> wrote:
>Yes, /dev/sda1 is my primary drive, and /dev/sda2 is the secondary drive
>in the ex-RAID. It is where the data I was wanting to get from the backup is.
Hopefully you mean *partition* rather than *drive* since both sda1 and sda2
are on the same physical disk. Not trying to nitpick, just making sure
we're both on the same page, which I'm not entirely sure we are. If
/dev/sda1 is "/" on the primary disk, then /dev/sda2 can't possibly be the
secondary drive - if you have a second physical SCSI drive then it would be
/dev/sdb. Physical drives are lettered a-z, partitions on the drives are
numbered and generally start with 1:
First SCSI disk = /dev/sda
First partition on first SCSI disk = /dev/sda1
Second partition on first SCSI disk = /dev/sda2
Third partition on first SCSI disk = /dev/sda3
Second SCSI disk = /dev/sdb
First partition on second SCSI disk = /dev/sdb1
Second partition on second SCSI disk = /dev/sdb2
...and so on. Follow me?
>You are right in the fact that this is an extended partition. There
>should be two partitions on it: 1) the mirror of "/" 2) the mirror of "swap".
If in fact you have a second physical drive then perhaps the old mirror of
"/" is on /dev/sdb1.
>==
>[root@login admin]# fdisk -l /dev/sda2
>{nothing}
Try it without the 2, eg: "fdisk -l /dev/sda". fdisk wants to look at the
whole disk and gets confused when you give it a partition.
>[root@login admin]# fdisk -l /dev/sda1
>Disk /dev/sda1: 255 heads, 63 sectors, 1045 cylinders
>Units = cylinders of 16065 * 512 bytes
>Disk /dev/sda1 doesn't contain a valid partition table
>==
Same thing - "fdisk -l /dev/sda"
>How would I go about mounting the old "/" off of /dev/sda2?
If in fact your secondary drive winds up being /dev/sdb1, then "mount
-text2 /dev/sdb1 /some/mount/point" should give you access to the old "/"
>Thanks for all your help
You're welcome - maybe we've got it this time. ;-)
-Eric
Eric Sisler
Library Computer Technician
Westminster Public Library
Westminster, CO, USA
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Re: RAID Question
Yes, /dev/sda1 is my primary drive, and /dev/sda2 is the secondary drive in the
ex-RAID. It is where the data I was wanting to get from the backup is.
You are right in the fact that this is an extended partition. There should be two
partitions on it: 1) the mirror of "/" 2) the mirror of "swap".
==
[root@login admin]# fdisk -l /dev/sda2
{nothing}
[root@login admin]# fdisk -l /dev/sda1
Disk /dev/sda1: 255 heads, 63 sectors, 1045 cylinders
Units = cylinders of 16065 * 512 bytes
Disk /dev/sda1 doesn't contain a valid partition table
==
How would I go about mounting the old "/" off of /dev/sda2?
Thanks for all your help.
Caleb Newville - MPS WebCrew
>>OK, my question is now "how do I mount it?". I want to mount the mirror
>>of the "/" partition from inside dev/sda2. Does me a lot of good having a
>>backup when I can't get inside it!
>
>Huh? I'm not following you. Your partition table looks like this
>according to fdisk:
>
> >Disk /dev/sda: 255 heads, 63 sectors, 1112 cylinders
> >Units = cylinders of 16065 * 512 bytes
> >
> >Device BootStart EndBlocks Id System
>>/dev/sda1 * 1 1046 8401963+ 83 Linux
>>/dev/sda2 1047 11125301455 Extended
>>/dev/sda5 1047 1112530113+ 82 Linux swap
>
>/dev/sda1 is a regular Linux ext2 partition and I would *guess* that it's
>probably mounted as "/"
>
>/dev/sda2 is an extended partition or to put it another way a "container"
>for other partitions. You can't directly mount it. Notice the start
>cylinder of 1047 and the end cylinder of 1112.
>
>/dev/sda5 is a logical partition, type 82 (Linux swap), contained within
>/dev/sda2. Notice the start/end cylinder values equal those of the
>extended partition. This means the swap partition is using all the
>available space in the extended partition. I'm also guessing that it's
>already mounted as your swap partition. Therefore, there's nothing left to
>mount on this disk. If this is your boot disk then perhaps your mirror of
>"/" is on a different physical drive? If there's more than one disk in the
>box run the same "fdisk -l" command on it - perhaps that's where your
>missing mirror is.
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Re: RAID Question
MPS WebCrew <[EMAIL PROTECTED]> wrote: >OK, my question is now "how do I mount it?". I want to mount the mirror >of the "/" partition from inside dev/sda2. Does me a lot of good having a >backup when I can't get inside it! Huh? I'm not following you. Your partition table looks like this according to fdisk: >Disk /dev/sda: 255 heads, 63 sectors, 1112 cylinders >Units = cylinders of 16065 * 512 bytes > >Device BootStart EndBlocks Id System >/dev/sda1 * 1 1046 8401963+ 83 Linux >/dev/sda2 1047 11125301455 Extended >/dev/sda5 1047 1112530113+ 82 Linux swap /dev/sda1 is a regular Linux ext2 partition and I would *guess* that it's probably mounted as "/" /dev/sda2 is an extended partition or to put it another way a "container" for other partitions. You can't directly mount it. Notice the start cylinder of 1047 and the end cylinder of 1112. /dev/sda5 is a logical partition, type 82 (Linux swap), contained within /dev/sda2. Notice the start/end cylinder values equal those of the extended partition. This means the swap partition is using all the available space in the extended partition. I'm also guessing that it's already mounted as your swap partition. Therefore, there's nothing left to mount on this disk. If this is your boot disk then perhaps your mirror of "/" is on a different physical drive? If there's more than one disk in the box run the same "fdisk -l" command on it - perhaps that's where your missing mirror is. -Eric Eric Sisler Library Computer Technician Westminster Public Library Westminster, CO, USA [EMAIL PROTECTED] Linux - don't fear the Penguin. Want to know what we use Linux for? Visit http://gromit.westminster.lib.co.us/linux ___ Redhat-list mailing list [EMAIL PROTECTED] https://listman.redhat.com/mailman/listinfo/redhat-list
Re: RAID Question
OK, my question is now "how do I mount it?". I want to mount the mirror of the "/" partition from inside dev/sda2. Does me a lot of good having a backup when I can't get inside it! Thanks! Caleb Newville - MPS WebCrew <<< [EMAIL PROTECTED] 4/12 10:26a >>> MPS WebCrew <[EMAIL PROTECTED]> wrote: >OK, here is the output from that: >--- >Disk /dev/sda: 255 heads, 63 sectors, 1112 cylinders >Units = cylinders of 16065 * 512 bytes > >Device BootStart EndBlocks Id System >/dev/sda1 * 1 1046 8401963+ 83 Linux >/dev/sda2 1047 11125301455 Extended >/dev/sda5 1047 1112530113+ 82 Linux swap >--- >And then: >--- >[root@login admin]# mount -t ext /dev/sda2 /mnt/old >mount: fs type ext not supported by kernel >--- >Now what!?! Thanks in advance! You can't mount an extended partition, only partitions within the extended partition. The only thing in there is a swap partition (sda5), so that won't help you much. Perhaps you meant to mount /dev/sda1, which is an ext2 partition, although not a RAID partition according to fdisk. Looking at your mount command, you're also trying to use the much older "ext" filesystem type. You'll want to use the newer ext2 type. HTH ___ Redhat-list mailing list [EMAIL PROTECTED] https://listman.redhat.com/mailman/listinfo/redhat-list
Re: RAID Question
MPS WebCrew <[EMAIL PROTECTED]> wrote: >OK, here is the output from that: >--- >Disk /dev/sda: 255 heads, 63 sectors, 1112 cylinders >Units = cylinders of 16065 * 512 bytes > >Device BootStart EndBlocks Id System >/dev/sda1 * 1 1046 8401963+ 83 Linux >/dev/sda2 1047 11125301455 Extended >/dev/sda5 1047 1112530113+ 82 Linux swap >--- >And then: >--- >[root@login admin]# mount -t ext /dev/sda2 /mnt/old >mount: fs type ext not supported by kernel >--- >Now what!?! Thanks in advance! You can't mount an extended partition, only partitions within the extended partition. The only thing in there is a swap partition (sda5), so that won't help you much. Perhaps you meant to mount /dev/sda1, which is an ext2 partition, although not a RAID partition according to fdisk. Looking at your mount command, you're also trying to use the much older "ext" filesystem type. You'll want to use the newer ext2 type. HTH -Eric Eric Sisler Library Computer Technician Westminster Public Library Westminster, CO, USA [EMAIL PROTECTED] Linux - don't fear the Penguin. Want to know what we use Linux for? Visit http://gromit.westminster.lib.co.us/linux ___ Redhat-list mailing list [EMAIL PROTECTED] https://listman.redhat.com/mailman/listinfo/redhat-list
Re: RAID Question
OK, here is the output from that: --- Disk /dev/sda: 255 heads, 63 sectors, 1112 cylinders Units = cylinders of 16065 * 512 bytes Device BootStart EndBlocks Id System /dev/sda1 * 1 1046 8401963+ 83 Linux /dev/sda2 1047 11125301455 Extended /dev/sda5 1047 1112530113+ 82 Linux swap --- And then: --- [root@login admin]# mount -t ext /dev/sda2 /mnt/old mount: fs type ext not supported by kernel --- Now what!?! Thanks in advance! Caleb Newville - MPS WebCrew <<< [EMAIL PROTECTED] 4/12 3:57a >>> On Wed, Apr 11, 2001 at 04:35:50PM -0500, MPS WebCrew a ecrit: > > I previously had RAID mirroring setup on 2 SCSI hard disks in RH 7.0 > [root@login admin]# mount -t ext2 /dev/sda2 /mnt/old > mount: wrong fs type, bad option, bad superblock on /dev/sda2, >or too many mounted file systems >(aren't you trying to mount an extended partition, >instead of some logical partition inside?) I'l pretty sure it's because the filesystem isn't ext2. [root@poe /root]# fdisk /dev/sda Command (m for help): p Disk /dev/sda: 64 heads, 32 sectors, 8755 cylinders Units = cylindres of 2048 * 512 bytes Device BootStart EndBlocks Id System /dev/sda1 1 513525296 fd Linux raid autodetect /dev/sda2 514 2050 1573888 fd Linux raid autodetect /dev/sda3 2051 4611 2622464 fd Linux raid autodetect /dev/sda4 4612 8755 42434565 Extended /dev/sda5 4612 5636 1049584 fd Linux raid autodetect /dev/sda6 5637 8755 3193840 fd Linux raid autodet Emmanuel Seyman ___ Redhat-list mailing list [EMAIL PROTECTED] https://listman.redhat.com/mailman/listinfo/redhat-list
Re: RAID Question
On Wed, Apr 11, 2001 at 04:35:50PM -0500, MPS WebCrew a ecrit: > > I previously had RAID mirroring setup on 2 SCSI hard disks in RH 7.0 > [root@login admin]# mount -t ext2 /dev/sda2 /mnt/old > mount: wrong fs type, bad option, bad superblock on /dev/sda2, >or too many mounted file systems >(aren't you trying to mount an extended partition, >instead of some logical partition inside?) I'l pretty sure it's because the filesystem isn't ext2. [root@poe /root]# fdisk /dev/sda Command (m for help): p Disk /dev/sda: 64 heads, 32 sectors, 8755 cylinders Units = cylindres of 2048 * 512 bytes Device BootStart EndBlocks Id System /dev/sda1 1 513525296 fd Linux raid autodetect /dev/sda2 514 2050 1573888 fd Linux raid autodetect /dev/sda3 2051 4611 2622464 fd Linux raid autodetect /dev/sda4 4612 8755 42434565 Extended /dev/sda5 4612 5636 1049584 fd Linux raid autodetect /dev/sda6 5637 8755 3193840 fd Linux raid autodet Emmanuel Seyman ___ Redhat-list mailing list [EMAIL PROTECTED] https://listman.redhat.com/mailman/listinfo/redhat-list
